The Wireless Priority Service (WPS) is a National Security/Emergency Preparedness (NS/EP) program that provides priority cellular network access to authorized individuals. The requirements for this service are set forth in the “Wireless Priority Service (WPS) Industry Requirements for the Full Operating Capability (FOC) for CDMA-Based Systems—Home Location Register (Issue 1.0),” which provides for the queuing of WPS call originations and National Security and Emergency Preparedness (NS/EP) call terminations when a radio channel is not available. In addition, further requirements are set forth in “The Development of Operational Technical and Spectrum Requirements for Meeting Federal, State and Local Public Safety Agency Communication Requirements Through the Year 2010” by the Federal Communications Commission, which addresses the concerns of wireless service providers that a large number of WPS users might congregate in a geographic serving area resulting in an unreasonable level of service denial for public users.
The above requirements document specifies general rules and characteristics of an algorithm, called Hard Public Use Reservation by Departure Allocation (H-PURDA), for allocating priority calls in a WPS system. The requirements documents do not however specify the manner in which the H-PURDA must be implemented.